火箭射流对RBCC进气道性能的影响

Rocket jet effect on the performance of a RBCC inlet

关键词:  火箭基组合循环  进气道  火箭射流  引射  数值仿真

Key words:  RBCC  Inlet  Rocket jet  Ejector  Numerical simulation

摘要:

火箭基组合循环(RBCC)推进系统在引射模态时存在火箭发动机和冲压发动机的共同工作,为了分析引射模态时进气道的性能和流场特征,根据RBCC的特点,设计了一种RBCC用二元式进气道,采用数值模拟方法研究了不同飞行高度、马赫数和掺混段反压下火箭射流对进气道性能的影响。研究发现,火箭发动机的工作状态决定了火箭射流对进气道性能的影响:当火箭发动机工作在过膨胀状态时,火箭射流的引射抽吸作用明显提高了推进系统的抗反压能力,但并不改善进气道的起动能力;当火箭发动机工作在欠膨胀状态时,火箭射流的压力扰动会使进气道扩压段产生结尾激波,进气道性能随之改变。

Abstract:

To investigate the performance of RBCC inlets in ejector mode,a 2-D inlet was designed for the rocket based combined cycle (RBCC),and the rocket jet effect on the performance of the RBCC inlet was discussed. The study found that the state of rocket jet decides its effect on the performance of the inlet. When rocket jet is over-expanded,the ejector effect of rocket jet can increase the anti-pressure ability of the RBCC inlet significantly,but it does not change the start Mach number of the inlet. When rocket jet is under-expanded,the high pressure of rocket jet can induce a shock in the diffuser section of the inlet,which changes the performance of the inlet.